Hitoaki Owashi

A field memory system for home-video editing

A multifunction field memory system with a time base corrector (TBC) suitable for mixing or editing two pictures has been developed. The mixing technology relies on a soft lock method which prevents disorder of the output signal when the external signal is switched. Skew correction in the search mode is also described. By using a dual-port memory, signals with phase discontinuity are replaced by regular signals. For the signal processing, two gate-array ICs have been developed. The system is outlined, the synchronization technique used for mixing is examined, the skew corrector is described, and other functions are briefly discussed. >

Linear Phase Emphasis Networks with Gaussian Function

In this paper, a new approach to the practical design and realization methods of linear phase emphasis network, which is applicable to the FM transmission system, is introduced. The methods are based on employing the Gaussian function expressed as a real exponential function exp(P2) realized by the squared amplitude response of a specific two-port passive LC ladder network. They are also based on a time base conversion technique using digital technology which provides a zero phase network.

Linear Phase Networks With Hyperbolic Tangent Function and Their Applications

This paper describes several methods to realize passive and active networks. with linear phase frequency response applicable to the video signal processing circuit especially for the FM transmission system. The methods are based on employing the hyperbolic tangent function realized by using passive LC ladder networks. They are also based on a time base conversion technique which provides the zero phase network. Using these methods, video signal processing circuits with linear phase property such as pre-emphasis and de-emphasis networks for the FM transmission TV system are introduced.

Improvement of Picture Quality in Variable Play of D-2 VTR: Field Conversion System Using Motion Adaptive Signal Processing

We have developed a motion-adaptive field conversion system for nonstandard speed play of a D-2 composite VCR. It employs a combination of a Y/C separation technique and a line-interpolation technique which adaptively uses interfield signals. We have also developed a new motion detecting method. This method adds interfield motion detection by level comparison to a conventional method using a temporal-spatial filter. With those techniques, it has become possible to improve the periodical displacement of vertical transitions, deterioration of vertical resolution, flicker in the chrominance signal, and other undesired effects. So picture quality equal to that of normal play mode was obtained in nonstandard-speed play mode.

Quick-response time base correction for analog segment recording VTR.

アナログセグメント記録方式高品位VTR用の時間軸処理方式として, 時間軸補正の高精度化と安定性・高速性を両立できる, フィードフォワード制御形式のバーストインジェクション時間軸補正方式が, 筆者らによって提案されている.本論文では, この時間軸補正方式の設計の一手法を確立するために, 非線形動作のインジェクション発振器を基本周波数にのみ着目して線形モデル化し, インジェクション信号に対する位相応答解析を行い, 発振器のQとインジェクション信号の瞬断による位相過渡応答との相関ならびに系の耐雑音特性を回路シミュレーションにより求めた.その結果, 発振器のQの最適化と定位相制御型PLLの併用により, バースト期間1μs以内で定常位相偏差を5ns以下に整定でき, 映像信号のS/Nが25dB程度に低下してもノイズ性ジッタを5ns以下に抑圧できることを確認し, 耐雑音の良好な高速・高精度の時間軸処理が実現可能であることを明らかにした.